The package nlohmann-json provides CMake targets:

    find_package(nlohmann_json CONFIG REQUIRED)
    target_link_libraries(main PRIVATE nlohmann_json::nlohmann_json)

The package nlohmann-json can be configured to not provide implicit conversions via a custom triplet file:

    set(nlohmann-json_IMPLICIT_CONVERSIONS OFF)

For more information, see the docs here:
    
    https://json.nlohmann.me/api/macros/json_use_implicit_conversions/